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lower_crossing_time_lt_of_lt_upcrossings_before (hN : 0 < N) (hab : a < b) (hn : n < upcrossings_before a b f N ω) : lower_crossing_time a b f N n ω < N
lt_of_le_of_lt lower_crossing_time_le_upper_crossing_time_succ (upper_crossing_time_lt_of_le_upcrossings_before hN hab hn)
lemma
measure_theory.lower_crossing_time_lt_of_lt_upcrossings_before
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_sub_of_le_upcrossings_before (hN : 0 < N) (hab : a < b) (hn : n < upcrossings_before a b f N ω) : b - a ≤ stopped_value f (upper_crossing_time a b f N (n + 1)) ω - stopped_value f (lower_crossing_time a b f N n) ω
sub_le_sub (stopped_value_upper_crossing_time (upper_crossing_time_lt_of_le_upcrossings_before hN hab hn).ne) (stopped_value_lower_crossing_time (lower_crossing_time_lt_of_lt_upcrossings_before hN hab hn).ne)
lemma
measure_theory.le_sub_of_le_upcrossings_before
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_eq_zero_of_upcrossings_before_lt (hab : a < b) (hn : upcrossings_before a b f N ω < n) : stopped_value f (upper_crossing_time a b f N (n + 1)) ω - stopped_value f (lower_crossing_time a b f N n) ω = 0
begin have : N ≤ upper_crossing_time a b f N n ω, { rw upcrossings_before at hn, rw ← not_lt, exact λ h, not_le.2 hn (le_cSup (upper_crossing_time_lt_bdd_above hab) h) }, simp [stopped_value, upper_crossing_time_stabilize' (nat.le_succ n) this, lower_crossing_time_stabilize' le_rfl (le_trans thi...
lemma
measure_theory.sub_eq_zero_of_upcrossings_before_lt
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "le_cSup", "le_rfl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_upcrossings_before_le (hf : a ≤ f N ω) (hab : a < b) : (b - a) * upcrossings_before a b f N ω ≤ ∑ k in finset.range N, upcrossing_strat a b f N k ω * (f (k + 1) - f k) ω
begin classical, by_cases hN : N = 0, { simp [hN] }, simp_rw [upcrossing_strat, finset.sum_mul, ← set.indicator_mul_left, pi.one_apply, pi.sub_apply, one_mul], rw finset.sum_comm, have h₁ : ∀ k, ∑ n in finset.range N, (set.Ico (lower_crossing_time a b f N k ω) (upper_crossing_time a b f N (k + 1) ω)...
lemma
measure_theory.mul_upcrossings_before_le
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "and_iff_right_iff_imp", "and_imp", "finset.Ico", "finset.card_range", "finset.filter", "finset.mem_Ico", "finset.mem_filter", "finset.mem_range", "finset.range", "finset.sum_mul", "mul_comm", "nsmul_eq_mul", "one_mul", "pi.one_apply", "set.Ico", "set.indicator_mul_left", "set.mem_Ic...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_mul_upcrossings_before_le_integral [is_finite_measure μ] (hf : submartingale f ℱ μ) (hfN : ∀ ω, a ≤ f N ω) (hfzero : 0 ≤ f 0) (hab : a < b) : (b - a) * μ[upcrossings_before a b f N] ≤ μ[f N]
calc (b - a) * μ[upcrossings_before a b f N] ≤ μ[∑ k in finset.range N, upcrossing_strat a b f N k * (f (k + 1) - f k)] : begin rw ← integral_mul_left, refine integral_mono_of_nonneg _ ((hf.sum_upcrossing_strat_mul a b N).integrable N) _, { exact eventually_of_forall (λ ω, mul_nonneg (sub_nonneg.2 hab.le) (na...
lemma
measure_theory.integral_mul_upcrossings_before_le_integral
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "finset.range", "nat.cast_nonneg" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
crossing_pos_eq (hab : a < b) : upper_crossing_time 0 (b - a) (λ n ω, (f n ω - a)⁺) N n = upper_crossing_time a b f N n ∧ lower_crossing_time 0 (b - a) (λ n ω, (f n ω - a)⁺) N n = lower_crossing_time a b f N n
begin have hab' : 0 < b - a := sub_pos.2 hab, have hf : ∀ ω i, b - a ≤ (f i ω - a)⁺ ↔ b ≤ f i ω, { intros i ω, refine ⟨λ h, _, λ h, _⟩, { rwa [← sub_le_sub_iff_right a, ← lattice_ordered_comm_group.pos_eq_self_of_pos_pos (lt_of_lt_of_le hab' h)] }, { rw ← sub_le_sub_iff_right a at h, rwa...
lemma
measure_theory.crossing_pos_eq
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "ih", "set.mem_Icc", "set.mem_Ici", "set.mem_Iic", "tsub_le_iff_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
upcrossings_before_pos_eq (hab : a < b) : upcrossings_before 0 (b - a) (λ n ω, (f n ω - a)⁺) N ω = upcrossings_before a b f N ω
by simp_rw [upcrossings_before, (crossing_pos_eq hab).1]
lemma
measure_theory.upcrossings_before_pos_eq
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_integral_upcrossings_before_le_integral_pos_part_aux [is_finite_measure μ] (hf : submartingale f ℱ μ) (hab : a < b) : (b - a) * μ[upcrossings_before a b f N] ≤ μ[λ ω, (f N ω - a)⁺]
begin refine le_trans (le_of_eq _) (integral_mul_upcrossings_before_le_integral (hf.sub_martingale (martingale_const _ _ _)).pos (λ ω, lattice_ordered_comm_group.pos_nonneg _) (λ ω, lattice_ordered_comm_group.pos_nonneg _) (sub_pos.2 hab)), simp_rw [sub_zero, ← upcrossings_before_pos_eq hab], refl, en...
lemma
measure_theory.mul_integral_upcrossings_before_le_integral_pos_part_aux
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
submartingale.mul_integral_upcrossings_before_le_integral_pos_part [is_finite_measure μ] (a b : ℝ) (hf : submartingale f ℱ μ) (N : ℕ) : (b - a) * μ[upcrossings_before a b f N] ≤ μ[λ ω, (f N ω - a)⁺]
begin by_cases hab : a < b, { exact mul_integral_upcrossings_before_le_integral_pos_part_aux hf hab }, { rw [not_lt, ← sub_nonpos] at hab, exact le_trans (mul_nonpos_of_nonpos_of_nonneg hab (integral_nonneg (λ ω, nat.cast_nonneg _))) (integral_nonneg (λ ω, lattice_ordered_comm_group.pos_nonneg _)) } end
theorem
measure_theory.submartingale.mul_integral_upcrossings_before_le_integral_pos_part
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "mul_nonpos_of_nonpos_of_nonneg", "nat.cast_nonneg" ]
**Doob's upcrossing estimate**: given a real valued discrete submartingale `f` and real values `a` and `b`, we have `(b - a) * 𝔼[upcrossings_before a b f N] ≤ 𝔼[(f N - a)⁺]` where `upcrossings_before a b f N` is the number of times the process `f` crossed from below `a` to above `b` before the time `N`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
upcrossings_before_eq_sum (hab : a < b) : upcrossings_before a b f N ω = ∑ i in finset.Ico 1 (N + 1), {n | upper_crossing_time a b f N n ω < N}.indicator 1 i
begin by_cases hN : N = 0, { simp [hN] }, rw ← finset.sum_Ico_consecutive _ (nat.succ_le_succ zero_le') (nat.succ_le_succ (upcrossings_before_le f ω hab)), have h₁ : ∀ k ∈ finset.Ico 1 (upcrossings_before a b f N ω + 1), {n : ℕ | upper_crossing_time a b f N n ω < N}.indicator 1 k = 1, { rintro k hk, ...
lemma
measure_theory.upcrossings_before_eq_sum
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "finset.Ico", "finset.mem_Ico", "mul_one", "mul_zero", "nat.add_succ_sub_one", "nat.card_Ico", "nat.succ_le_iff", "smul_eq_mul", "zero_le'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
adapted.measurable_upcrossings_before (hf : adapted ℱ f) (hab : a < b) : measurable (upcrossings_before a b f N)
begin have : upcrossings_before a b f N = λ ω, ∑ i in finset.Ico 1 (N + 1), {n | upper_crossing_time a b f N n ω < N}.indicator 1 i, { ext ω, exact upcrossings_before_eq_sum hab }, rw this, exact finset.measurable_sum _ (λ i hi, measurable.indicator measurable_const $ ℱ.le N _ (hf.is_stopping_time_u...
lemma
measure_theory.adapted.measurable_upcrossings_before
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "finset.Ico", "measurable", "measurable.indicator", "measurable_const" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
adapted.integrable_upcrossings_before [is_finite_measure μ] (hf : adapted ℱ f) (hab : a < b) : integrable (λ ω, (upcrossings_before a b f N ω : ℝ)) μ
begin have : ∀ᵐ ω ∂μ, ‖(upcrossings_before a b f N ω : ℝ)‖ ≤ N, { refine eventually_of_forall (λ ω, _), rw [real.norm_eq_abs, nat.abs_cast, nat.cast_le], refine upcrossings_before_le _ _ hab }, exact ⟨measurable.ae_strongly_measurable (measurable_from_top.comp (hf.measurable_upcrossings_before hab)), ...
lemma
measure_theory.adapted.integrable_upcrossings_before
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "nat.abs_cast", "nat.cast_le", "real.norm_eq_abs" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
upcrossings [preorder ι] [order_bot ι] [has_Inf ι] (a b : ℝ) (f : ι → Ω → ℝ) (ω : Ω) : ℝ≥0∞
⨆ N, (upcrossings_before a b f N ω : ℝ≥0∞)
def
measure_theory.upcrossings
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "has_Inf", "order_bot" ]
The number of upcrossings of a realization of a stochastic process (`upcrossing` takes value in `ℝ≥0∞` and so is allowed to be `∞`).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
adapted.measurable_upcrossings (hf : adapted ℱ f) (hab : a < b) : measurable (upcrossings a b f)
measurable_supr (λ N, measurable_from_top.comp (hf.measurable_upcrossings_before hab))
lemma
measure_theory.adapted.measurable_upcrossings
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "measurable", "measurable_supr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
upcrossings_lt_top_iff : upcrossings a b f ω < ∞ ↔ ∃ k, ∀ N, upcrossings_before a b f N ω ≤ k
begin have : upcrossings a b f ω < ∞ ↔ ∃ k : ℝ≥0, upcrossings a b f ω ≤ k, { split, { intro h, lift upcrossings a b f ω to ℝ≥0 using h.ne with r hr, exact ⟨r, le_rfl⟩ }, { rintro ⟨k, hk⟩, exact lt_of_le_of_lt hk ennreal.coe_lt_top } }, simp_rw [this, upcrossings, supr_le_iff], split; r...
lemma
measure_theory.upcrossings_lt_top_iff
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "ennreal.coe_le_coe", "ennreal.coe_lt_top", "ennreal.coe_nat", "exists_nat_ge", "lift", "nat.cast_le", "supr_le_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
submartingale.mul_lintegral_upcrossings_le_lintegral_pos_part [is_finite_measure μ] (a b : ℝ) (hf : submartingale f ℱ μ) : ennreal.of_real (b - a) * ∫⁻ ω, upcrossings a b f ω ∂μ ≤ ⨆ N, ∫⁻ ω, ennreal.of_real ((f N ω - a)⁺) ∂μ
begin by_cases hab : a < b, { simp_rw [upcrossings], have : ∀ N, ∫⁻ ω, ennreal.of_real ((f N ω - a)⁺) ∂μ = ennreal.of_real (∫ ω, (f N ω - a)⁺ ∂μ), { intro N, rw of_real_integral_eq_lintegral_of_real, { exact (hf.sub_martingale (martingale_const _ _ _)).pos.integrable _ }, { exact eventuall...
lemma
measure_theory.submartingale.mul_lintegral_upcrossings_le_lintegral_pos_part
probability.martingale
src/probability/martingale/upcrossing.lean
[ "data.set.intervals.monotone", "probability.process.hitting_time", "probability.martingale.basic" ]
[ "ae_measurable", "ennreal.mul_supr", "ennreal.of_real", "ennreal.of_real_le_of_real", "ennreal.of_real_mul", "le_supr", "nat.cast_le", "nnreal.coe_nat_cast", "supr_le_iff", "zero_mul" ]
A variant of Doob's upcrossing estimate obtained by taking the supremum on both sides.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
{u} pmf (α : Type u) : Type u
{ f : α → ℝ≥0∞ // has_sum f 1 }
def
pmf
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "has_sum" ]
A probability mass function, or discrete probability measures is a function `α → ℝ≥0∞` such that the values have (infinite) sum `1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fun_like : fun_like (pmf α) α (λ p, ℝ≥0∞)
{ coe := λ p a, p.1 a, coe_injective' := λ p q h, subtype.eq h }
instance
pmf.fun_like
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "fun_like", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext {p q : pmf α} (h : ∀ x, p x = q x) : p = q
fun_like.ext p q h
lemma
pmf.ext
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "fun_like.ext", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext_iff {p q : pmf α} : p = q ↔ ∀ x, p x = q x
fun_like.ext_iff
lemma
pmf.ext_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "fun_like.ext_iff", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_sum_coe_one (p : pmf α) : has_sum p 1
p.2
lemma
pmf.has_sum_coe_one
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "has_sum", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tsum_coe (p : pmf α) : ∑' a, p a = 1
p.has_sum_coe_one.tsum_eq
lemma
pmf.tsum_coe
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tsum_coe_ne_top (p : pmf α) : ∑' a, p a ≠ ∞
p.tsum_coe.symm ▸ ennreal.one_ne_top
lemma
pmf.tsum_coe_ne_top
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "ennreal.one_ne_top", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tsum_coe_indicator_ne_top (p : pmf α) (s : set α) : ∑' a, s.indicator p a ≠ ∞
ne_of_lt (lt_of_le_of_lt (tsum_le_tsum (λ a, set.indicator_apply_le (λ _, le_rfl)) ennreal.summable ennreal.summable) (lt_of_le_of_ne le_top p.tsum_coe_ne_top))
lemma
pmf.tsum_coe_indicator_ne_top
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "ennreal.summable", "le_rfl", "le_top", "pmf", "tsum_le_tsum" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_ne_zero (p : pmf α) : ⇑p ≠ 0
λ hp, zero_ne_one ((tsum_zero.symm.trans (tsum_congr $ λ x, symm (congr_fun hp x))).trans p.tsum_coe)
lemma
pmf.coe_ne_zero
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf", "tsum_congr", "zero_ne_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support (p : pmf α) : set α
function.support p
def
pmf.support
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "function.support", "pmf" ]
The support of a `pmf` is the set where it is nonzero.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_support_iff (p : pmf α) (a : α) : a ∈ p.support ↔ p a ≠ 0
iff.rfl
lemma
pmf.mem_support_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_nonempty (p : pmf α) : p.support.nonempty
function.support_nonempty_iff.2 p.coe_ne_zero
lemma
pmf.support_nonempty
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_eq_zero_iff (p : pmf α) (a : α) : p a = 0 ↔ a ∉ p.support
by rw [mem_support_iff, not_not]
lemma
pmf.apply_eq_zero_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "not_not", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_pos_iff (p : pmf α) (a : α) : 0 < p a ↔ a ∈ p.support
pos_iff_ne_zero.trans (p.mem_support_iff a).symm
lemma
pmf.apply_pos_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_eq_one_iff (p : pmf α) (a : α) : p a = 1 ↔ p.support = {a}
begin refine ⟨λ h, set.subset.antisymm (λ a' ha', by_contra $ λ ha, _) (λ a' ha', ha'.symm ▸ (p.mem_support_iff a).2 (λ ha, zero_ne_one $ ha.symm.trans h)), λ h, trans (symm $ tsum_eq_single a (λ a' ha', (p.apply_eq_zero_iff a').2 (h.symm ▸ ha'))) p.tsum_coe⟩, suffices : 1 < ∑' a, p a, from ne_of_lt thi...
lemma
pmf.apply_eq_one_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "by_contra", "ennreal.add_lt_add_of_le_of_lt", "ennreal.one_ne_top", "ennreal.summable", "le_rfl", "lt_of_le_of_ne'", "pmf", "set.subset.antisymm", "tsum_congr", "tsum_eq_single", "tsum_ne_zero_iff", "zero_le'", "zero_ne_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_le_one (p : pmf α) (a : α) : p a ≤ 1
has_sum_le (by { intro b, split_ifs; simp only [h, zero_le', le_rfl] }) (has_sum_ite_eq a (p a)) (has_sum_coe_one p)
lemma
pmf.coe_le_one
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "has_sum_ite_eq", "has_sum_le", "le_rfl", "pmf", "zero_le'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_ne_top (p : pmf α) (a : α) : p a ≠ ∞
ne_of_lt (lt_of_le_of_lt (p.coe_le_one a) ennreal.one_lt_top)
lemma
pmf.apply_ne_top
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "ennreal.one_lt_top", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_lt_top (p : pmf α) (a : α) : p a < ∞
lt_of_le_of_ne le_top (p.apply_ne_top a)
lemma
pmf.apply_lt_top
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "le_top", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure (p : pmf α) : outer_measure α
outer_measure.sum (λ (x : α), p x • dirac x)
def
pmf.to_outer_measure
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf" ]
Construct an `outer_measure` from a `pmf`, by assigning measure to each set `s : set α` equal to the sum of `p x` for for each `x ∈ α`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply : p.to_outer_measure s = ∑' x, s.indicator p x
tsum_congr (λ x, smul_dirac_apply (p x) x s)
lemma
pmf.to_outer_measure_apply
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "tsum_congr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_caratheodory : p.to_outer_measure.caratheodory = ⊤
begin refine (eq_top_iff.2 $ le_trans (le_Inf $ λ x hx, _) (le_sum_caratheodory _)), exact let ⟨y, hy⟩ := hx in ((le_of_eq (dirac_caratheodory y).symm).trans (le_smul_caratheodory _ _)).trans (le_of_eq hy), end
lemma
pmf.to_outer_measure_caratheodory
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "le_Inf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply_finset (s : finset α) : p.to_outer_measure s = ∑ x in s, p x
begin refine (to_outer_measure_apply p s).trans ((@tsum_eq_sum _ _ _ _ _ _ s _).trans _), { exact λ x hx, set.indicator_of_not_mem hx _ }, { exact finset.sum_congr rfl (λ x hx, set.indicator_of_mem hx _) } end
lemma
pmf.to_outer_measure_apply_finset
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "finset", "tsum_eq_sum" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply_singleton (a : α) : p.to_outer_measure {a} = p a
begin refine (p.to_outer_measure_apply {a}).trans ((tsum_eq_single a $ λ b hb, _).trans _), { exact ite_eq_right_iff.2 (λ hb', false.elim $ hb hb') }, { exact ite_eq_left_iff.2 (λ ha', false.elim $ ha' rfl) } end
lemma
pmf.to_outer_measure_apply_singleton
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "tsum_eq_single" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_injective : (to_outer_measure : pmf α → outer_measure α).injective
λ p q h, pmf.ext (λ x, (p.to_outer_measure_apply_singleton x).symm.trans ((congr_fun (congr_arg _ h) _).trans $ q.to_outer_measure_apply_singleton x))
lemma
pmf.to_outer_measure_injective
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf", "pmf.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_inj {p q : pmf α} : p.to_outer_measure = q.to_outer_measure ↔ p = q
to_outer_measure_injective.eq_iff
lemma
pmf.to_outer_measure_inj
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply_eq_zero_iff : p.to_outer_measure s = 0 ↔ disjoint p.support s
begin rw [to_outer_measure_apply, ennreal.tsum_eq_zero], exact function.funext_iff.symm.trans set.indicator_eq_zero', end
lemma
pmf.to_outer_measure_apply_eq_zero_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "disjoint", "ennreal.tsum_eq_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply_eq_one_iff : p.to_outer_measure s = 1 ↔ p.support ⊆ s
begin refine (p.to_outer_measure_apply s).symm ▸ ⟨λ h a hap, _, λ h, _⟩, { refine by_contra (λ hs, ne_of_lt _ (h.trans p.tsum_coe.symm)), have hs' : s.indicator p a = 0 := set.indicator_apply_eq_zero.2 (λ hs', false.elim $ hs hs'), have hsa : s.indicator p a < p a := hs'.symm ▸ (p.apply_pos_iff a).2 hap, ...
lemma
pmf.to_outer_measure_apply_eq_one_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "by_contra", "ennreal.tsum_lt_tsum", "le_rfl", "set.not_mem_subset", "tsum_congr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply_inter_support : p.to_outer_measure (s ∩ p.support) = p.to_outer_measure s
by simp only [to_outer_measure_apply, pmf.support, set.indicator_inter_support]
lemma
pmf.to_outer_measure_apply_inter_support
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf.support" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_mono {s t : set α} (h : s ∩ p.support ⊆ t) : p.to_outer_measure s ≤ p.to_outer_measure t
le_trans (le_of_eq (to_outer_measure_apply_inter_support p s).symm) (p.to_outer_measure.mono h)
lemma
pmf.to_outer_measure_mono
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[]
Slightly stronger than `outer_measure.mono` having an intersection with `p.support`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply_eq_of_inter_support_eq {s t : set α} (h : s ∩ p.support = t ∩ p.support) : p.to_outer_measure s = p.to_outer_measure t
le_antisymm (p.to_outer_measure_mono (h.symm ▸ (set.inter_subset_left t p.support))) (p.to_outer_measure_mono (h ▸ (set.inter_subset_left s p.support)))
lemma
pmf.to_outer_measure_apply_eq_of_inter_support_eq
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "set.inter_subset_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply_fintype [fintype α] : p.to_outer_measure s = ∑ x, s.indicator p x
(p.to_outer_measure_apply s).trans (tsum_eq_sum (λ x h, absurd (finset.mem_univ x) h))
lemma
pmf.to_outer_measure_apply_fintype
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "finset.mem_univ", "fintype", "tsum_eq_sum" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure [measurable_space α] (p : pmf α) : measure α
p.to_outer_measure.to_measure ((to_outer_measure_caratheodory p).symm ▸ le_top)
def
pmf.to_measure
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "le_top", "measurable_space", "pmf" ]
Since every set is Carathéodory-measurable under `pmf.to_outer_measure`, we can further extend this `outer_measure` to a `measure` on `α`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_apply_le_to_measure_apply : p.to_outer_measure s ≤ p.to_measure s
le_to_measure_apply p.to_outer_measure _ s
lemma
pmf.to_outer_measure_apply_le_to_measure_apply
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_eq_to_outer_measure_apply (hs : measurable_set s) : p.to_measure s = p.to_outer_measure s
to_measure_apply p.to_outer_measure _ hs
lemma
pmf.to_measure_apply_eq_to_outer_measure_apply
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply (hs : measurable_set s) : p.to_measure s = ∑' x, s.indicator p x
(p.to_measure_apply_eq_to_outer_measure_apply s hs).trans (p.to_outer_measure_apply s)
lemma
pmf.to_measure_apply
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_singleton (a : α) (h : measurable_set ({a} : set α)) : p.to_measure {a} = p a
by simp [to_measure_apply_eq_to_outer_measure_apply _ _ h, to_outer_measure_apply_singleton]
lemma
pmf.to_measure_apply_singleton
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_eq_zero_iff (hs : measurable_set s) : p.to_measure s = 0 ↔ disjoint p.support s
by rw [to_measure_apply_eq_to_outer_measure_apply p s hs, to_outer_measure_apply_eq_zero_iff]
lemma
pmf.to_measure_apply_eq_zero_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "disjoint", "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_eq_one_iff (hs : measurable_set s) : p.to_measure s = 1 ↔ p.support ⊆ s
(p.to_measure_apply_eq_to_outer_measure_apply s hs : p.to_measure s = p.to_outer_measure s).symm ▸ (p.to_outer_measure_apply_eq_one_iff s)
lemma
pmf.to_measure_apply_eq_one_iff
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_inter_support (hs : measurable_set s) (hp : measurable_set p.support) : p.to_measure (s ∩ p.support) = p.to_measure s
by simp [p.to_measure_apply_eq_to_outer_measure_apply s hs, p.to_measure_apply_eq_to_outer_measure_apply _ (hs.inter hp)]
lemma
pmf.to_measure_apply_inter_support
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_mono {s t : set α} (hs : measurable_set s) (ht : measurable_set t) (h : s ∩ p.support ⊆ t) : p.to_measure s ≤ p.to_measure t
by simpa only [p.to_measure_apply_eq_to_outer_measure_apply, hs, ht] using to_outer_measure_mono p h
lemma
pmf.to_measure_mono
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_eq_of_inter_support_eq {s t : set α} (hs : measurable_set s) (ht : measurable_set t) (h : s ∩ p.support = t ∩ p.support) : p.to_measure s = p.to_measure t
by simpa only [p.to_measure_apply_eq_to_outer_measure_apply, hs, ht] using to_outer_measure_apply_eq_of_inter_support_eq p h
lemma
pmf.to_measure_apply_eq_of_inter_support_eq
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "measurable_set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_injective : (to_measure : pmf α → measure α).injective
λ p q h, pmf.ext (λ x, (p.to_measure_apply_singleton x $ measurable_set_singleton x).symm.trans ((congr_fun (congr_arg _ h) _).trans $ q.to_measure_apply_singleton x $ measurable_set_singleton x))
lemma
pmf.to_measure_injective
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf", "pmf.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_inj {p q : pmf α} : p.to_measure = q.to_measure ↔ p = q
to_measure_injective.eq_iff
lemma
pmf.to_measure_inj
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_finset (s : finset α) : p.to_measure s = ∑ x in s, p x
(p.to_measure_apply_eq_to_outer_measure_apply s s.measurable_set).trans (p.to_outer_measure_apply_finset s)
lemma
pmf.to_measure_apply_finset
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_of_finite (hs : s.finite) : p.to_measure s = ∑' x, s.indicator p x
(p.to_measure_apply_eq_to_outer_measure_apply s hs.measurable_set).trans (p.to_outer_measure_apply s)
lemma
pmf.to_measure_apply_of_finite
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_apply_fintype [fintype α] : p.to_measure s = ∑ x, s.indicator p x
(p.to_measure_apply_eq_to_outer_measure_apply s s.to_finite.measurable_set).trans (p.to_outer_measure_apply_fintype s)
lemma
pmf.to_measure_apply_fintype
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "fintype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_pmf [countable α] [measurable_space α] [measurable_singleton_class α] (μ : measure α) [h : is_probability_measure μ] : pmf α
⟨λ x, μ ({x} : set α), ennreal.summable.has_sum_iff.2 (trans (symm $ (tsum_indicator_apply_singleton μ set.univ measurable_set.univ).symm.trans (tsum_congr (λ x, congr_fun (set.indicator_univ _) x))) (h.measure_univ))⟩
def
measure_theory.measure.to_pmf
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "countable", "measurable_set.univ", "measurable_singleton_class", "measurable_space", "pmf", "tsum_congr" ]
Given that `α` is a countable, measurable space with all singleton sets measurable, we can convert any probability measure into a `pmf`, where the mass of a point is the measure of the singleton set under the original measure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_pmf_apply (x : α) : μ.to_pmf x = μ {x}
rfl
lemma
measure_theory.measure.to_pmf_apply
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_pmf_to_measure : μ.to_pmf.to_measure = μ
measure.ext (λ s hs, by simpa only [μ.to_pmf.to_measure_apply s hs, ← μ.tsum_indicator_apply_singleton s hs])
lemma
measure_theory.measure.to_pmf_to_measure
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure.is_probability_measure [measurable_space α] (p : pmf α) : is_probability_measure (p.to_measure)
⟨by simpa only [measurable_set.univ, to_measure_apply_eq_to_outer_measure_apply, set.indicator_univ, to_outer_measure_apply, ennreal.coe_eq_one] using tsum_coe p⟩
instance
pmf.to_measure.is_probability_measure
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "ennreal.coe_eq_one", "measurable_set.univ", "measurable_space", "pmf" ]
The measure associated to a `pmf` by `to_measure` is a probability measure
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_to_pmf : p.to_measure.to_pmf = p
pmf.ext (λ x, by rw [← p.to_measure_apply_singleton x (measurable_set_singleton x), p.to_measure.to_pmf_apply])
lemma
pmf.to_measure_to_pmf
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[ "pmf.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_eq_iff_eq_to_pmf (μ : measure α) [is_probability_measure μ] : p.to_measure = μ ↔ p = μ.to_pmf
by rw [← to_measure_inj, measure.to_pmf_to_measure]
lemma
pmf.to_measure_eq_iff_eq_to_pmf
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_pmf_eq_iff_to_measure_eq (μ : measure α) [is_probability_measure μ] : μ.to_pmf = p ↔ μ = p.to_measure
by rw [← to_measure_inj, measure.to_pmf_to_measure]
lemma
pmf.to_pmf_eq_iff_to_measure_eq
probability.probability_mass_function
src/probability/probability_mass_function/basic.lean
[ "topology.instances.ennreal", "measure_theory.measure.measure_space" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map (f : α → β) (p : pmf α) : pmf β
bind p (pure ∘ f)
def
pmf.map
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "pmf" ]
The functorial action of a function on a `pmf`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monad_map_eq_map {α β : Type*} (f : α → β) (p : pmf α) : f <$> p = p.map f
rfl
lemma
pmf.monad_map_eq_map
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_apply : (map f p) b = ∑' a, if b = f a then p a else 0
by simp [map]
lemma
pmf.map_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_map : (map f p).support = f '' p.support
set.ext (λ b, by simp [map, @eq_comm β b])
lemma
pmf.support_map
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "set.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_support_map_iff : b ∈ (map f p).support ↔ ∃ a ∈ p.support, f a = b
by simp
lemma
pmf.mem_support_map_iff
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bind_pure_comp : bind p (pure ∘ f) = map f p
rfl
lemma
pmf.bind_pure_comp
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_id : map id p = p
bind_pure _
lemma
pmf.map_id
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "map_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_comp (g : β → γ) : (p.map f).map g = p.map (g ∘ f)
by simp [map]
lemma
pmf.map_comp
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "map_comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pure_map (a : α) : (pure a).map f = pure (f a)
pure_bind _ _
lemma
pmf.pure_map
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_bind (q : α → pmf β) (f : β → γ) : (p.bind q).map f = p.bind (λ a, (q a).map f)
bind_bind _ _ _
lemma
pmf.map_bind
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "map_bind", "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bind_map (p : pmf α) (f : α → β) (q : β → pmf γ) : (p.map f).bind q = p.bind (q ∘ f)
(bind_bind _ _ _).trans (congr_arg _ (funext (λ a, pure_bind _ _)))
lemma
pmf.bind_map
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_const : p.map (function.const α b) = pure b
by simp only [map, bind_const, function.comp_const]
lemma
pmf.map_const
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "function.comp_const" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_map_apply : (p.map f).to_outer_measure s = p.to_outer_measure (f ⁻¹' s)
by simp [map, set.indicator, to_outer_measure_apply p (f ⁻¹' s)]
lemma
pmf.to_outer_measure_map_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "set.indicator" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_map_apply [measurable_space α] [measurable_space β] (hf : measurable f) (hs : measurable_set s) : (p.map f).to_measure s = p.to_measure (f ⁻¹' s)
begin rw [to_measure_apply_eq_to_outer_measure_apply _ s hs, to_measure_apply_eq_to_outer_measure_apply _ (f ⁻¹' s) (measurable_set_preimage hf hs)], exact to_outer_measure_map_apply f p s, end
lemma
pmf.to_measure_map_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "measurable", "measurable_set", "measurable_set_preimage", "measurable_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
seq (q : pmf (α → β)) (p : pmf α) : pmf β
q.bind (λ m, p.bind $ λ a, pure (m a))
def
pmf.seq
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "pmf" ]
The monadic sequencing operation for `pmf`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monad_seq_eq_seq {α β : Type*} (q : pmf (α → β)) (p : pmf α) : q <*> p = q.seq p
rfl
lemma
pmf.monad_seq_eq_seq
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "pmf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
seq_apply : (seq q p) b = ∑' (f : α → β) (a : α), if b = f a then q f * p a else 0
begin simp only [seq, mul_boole, bind_apply, pure_apply], refine tsum_congr (λ f, (ennreal.tsum_mul_left).symm.trans (tsum_congr (λ a, _))), simpa only [mul_zero] using mul_ite (b = f a) (q f) (p a) 0 end
lemma
pmf.seq_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "ennreal.tsum_mul_left", "mul_boole", "mul_ite", "mul_zero", "tsum_congr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_seq : (seq q p).support = ⋃ f ∈ q.support, f '' p.support
set.ext (λ b, by simp [-mem_support_iff, seq, @eq_comm β b])
lemma
pmf.support_seq
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "set.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_support_seq_iff : b ∈ (seq q p).support ↔ ∃ (f ∈ q.support), b ∈ f '' p.support
by simp
lemma
pmf.mem_support_seq_iff
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_finset (f : α → ℝ≥0∞) (s : finset α) (h : ∑ a in s, f a = 1) (h' : ∀ a ∉ s, f a = 0) : pmf α
⟨f, h ▸ has_sum_sum_of_ne_finset_zero h'⟩
def
pmf.of_finset
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "finset", "has_sum_sum_of_ne_finset_zero", "pmf" ]
Given a finset `s` and a function `f : α → ℝ≥0∞` with sum `1` on `s`, such that `f a = 0` for `a ∉ s`, we get a `pmf`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_finset_apply (a : α) : of_finset f s h h' a = f a
rfl
lemma
pmf.of_finset_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_of_finset : (of_finset f s h h').support = s ∩ (function.support f)
set.ext (λ a, by simpa [mem_support_iff] using mt (h' a))
lemma
pmf.support_of_finset
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "function.support", "set.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_support_of_finset_iff (a : α) : a ∈ (of_finset f s h h').support ↔ a ∈ s ∧ f a ≠ 0
by simp
lemma
pmf.mem_support_of_finset_iff
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_finset_apply_of_not_mem {a : α} (ha : a ∉ s) : of_finset f s h h' a = 0
h' a ha
lemma
pmf.of_finset_apply_of_not_mem
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_of_finset_apply : (of_finset f s h h').to_outer_measure t = ∑' x, t.indicator f x
to_outer_measure_apply (of_finset f s h h') t
lemma
pmf.to_outer_measure_of_finset_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_measure_of_finset_apply [measurable_space α] (ht : measurable_set t) : (of_finset f s h h').to_measure t = ∑' x, t.indicator f x
(to_measure_apply_eq_to_outer_measure_apply _ t ht).trans (to_outer_measure_of_finset_apply h h' t)
lemma
pmf.to_measure_of_finset_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "measurable_set", "measurable_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_fintype [fintype α] (f : α → ℝ≥0∞) (h : ∑ a, f a = 1) : pmf α
of_finset f finset.univ h (λ a ha, absurd (finset.mem_univ a) ha)
def
pmf.of_fintype
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "finset.mem_univ", "finset.univ", "fintype", "pmf" ]
Given a finite type `α` and a function `f : α → ℝ≥0∞` with sum 1, we get a `pmf`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_fintype_apply (a : α) : of_fintype f h a = f a
rfl
lemma
pmf.of_fintype_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_of_fintype : (of_fintype f h).support = function.support f
rfl
lemma
pmf.support_of_fintype
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[ "function.support" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_support_of_fintype_iff (a : α) : a ∈ (of_fintype f h).support ↔ f a ≠ 0
iff.rfl
lemma
pmf.mem_support_of_fintype_iff
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_outer_measure_of_fintype_apply : (of_fintype f h).to_outer_measure s = ∑' x, s.indicator f x
to_outer_measure_apply (of_fintype f h) s
lemma
pmf.to_outer_measure_of_fintype_apply
probability.probability_mass_function
src/probability/probability_mass_function/constructions.lean
[ "probability.probability_mass_function.monad" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83